Rotary cutting head having core burster means



June 7, 1960 w, ouN s o 2,939,690

ROTARY CUTTING HEAD HAVING CORE BuRsTER MEANS Original Filed June 16, 1955 2 Sheets-Sheet 1 IN V EN TOR. WILLIAM N. POUNDSTONE June 1950 w. N. POUNDSTONE' 2,939,690

ROTARY CUTTING HEAD HAVING CORE BURSTER MEANS Original Filed June 16, 1955 2 Sheets-Sheet 2 u I I 2| l5 INVENTOR.

WILLIAM N. POUNDSTONE 37L4 1 4?. Q

HIS ATTORNEY United. Stems Patent Original" application June 16, 1955, Ser. No. 515,?81. and tlilsiapplicalion Oct. 9, 1-9 58, Ser; No.

This invention relates to a rotary cutting head adapted to be used with a continuous mining machine of the general type that cuts circular kerfs in a vertical face of mineral, and more particularly, to a rotary cutting head having an improved core burster which breaks down and dislodges'the cores of mineral within the cir'-' cular kerfs. l

' The present application is a division of my copending. application Serial Number 515,982, filed June 16", 1955, now abandoned, and assigned to the assignee of the present; invention.

Among the many types of machines used td' continuously remove coal orother mineralsfroma seam or vein,; there is a type of machine generally designated as' the McKinlay mining machine. This machine'has a frame mounted on endless type treads which permits the-machine to tram or continuously advance into the seam as the mineral is removed. The frame is so constructed that the dislodged mineral is conveyed toward the rear of the machine 'bymeans of a longitudinal central conveyor system. The machine has a pair of spaced rotatable drive shafts extending horizontally from the front end of the housing and"'-rotatable cutting heads secured to the front ends of each of the drive shafts. The rotatable cutting headsare adapted to rotate ina plane parallel to the vertical face of -the mineral seam. The cutting} heads have arms extending radiallywherefrom with a plurality of cutter bits secured normal to the arms 'atthe radial end portions;

As the machine advances into the mineral seam, the bits attack the vertical face of mineral and cut annular kerfs therein. The present machines also have anaxially" positioned pilotbit that penetrates the mineral face 'in advance of the radial cutter bits and a conical breaker to break and dislodge the mineral within the circum-- ference of the annular kerf.

7 One of the difliculties experienced with this type of machine 'isthe tread slippage or loss of traction as the machine attempts to advance into the mineral seam. It has been found that one of the principal reasons for this tread slippage is the specific construction of the pilot bit and the conical breaker; The pilot bit, due to its axial position, has a relatively small amount of lineal motion in relation to the cutter bits extending from the arms. Thus thepilot bit literally drills into the mineral seam in advance of the cutter bits. This drilling action reduces the overall efficiencyof the mining machine be-- cause the penetration rate of the. pilot bit is limited by the rate of rotation of the: cutter head; Also the pilot bit and conical breakerarrangement fails to provide a. means to remove the cuttingsmade by the pilot bit. As the pilot bit penetrates to the-point where the conical breakencontacts the mineral face, the cuttings within theborelm'ade by the piloebit further obstruct the for-. ward. movement ofithe': mining machine due to the pres.- sm'e: exerted bytherciittings: against the front: edge; of: the conical Zbteaken. .'Iti"1has? also been..discovered that a large amount of energy is expended by the conical breaker 2,939,690 Patented June 7, i 1960 grinding into the. boreymade by the pilot bit. Thus in the Pr sent machine the rateof displacement or removal of the mineral is dependent, upon the rate at which. the pilot bit and. breaker penetrates. the mineral Seam V V p Accordingly with the above described difficulties in mind, the principal object ofthis invention is to provide Another object of; this invention isto. provide an improved core burster, having a central passageway therethrough and means to discharge the mined material from within this central passageway;

Another object of this, invention isto provide a rotary cutting head thatis efficient. in operation, economical and sturdy in construction, and relatively simple to as.- semble and maintain.

These and other objects and advantages of this invention. will be more, completely disclosed and described in the following specification, the accompanying drawings and the appended. claims.

Figure. 1 is. a view in front elevation of the mining machine with my improved rotary cutting heads posi-- tioned thereon; v

Figure. 2 is a. plan view of my improved rotary cutting head;

' Figure 3 is a view of my improved rotary cutting head inv front elevation; t I, Figure. 4 is a fragmentary sectional: view taken. along the line 4'-4 in Figure 2 showing my improved core mounted. on: endless treads, which are not shown, so that the. machine can move forwardas themineral removed. from the, seam. The frame carries driving which. are operable to rotate the pair of horizontal spaced drive shafts 1 1 extendingffrom the front portion of the machine and also operable to drive the cutter chains 12 in a conventional manner. The, housing 10 has a longitudinal central passageway extending theretlirough and a conveyor means 13 which is adapted to remove dislodged mineral from the front of the, machine. Rotatably secured to the shafts 11 are rotary cutting heads 14 positioned substantially out of time to each other and operable to rotate in opposite. directions. For example, the cutting head on the rightv side of Figure l rotates in a clockwise direction andthe cutter head on the left side rotates in a. counterclockwise direction. Paddle members 15 are adapted to scoop the dislodged mineral from in front of the machine into the conveyor means 13 thereby clear-inga path so that the machine can advance into the seam. Each of the rotary cutting heads has cutting means positioned on its. outer edge which cuts into the face of, mineral and dislodges.

' rotarycutting heads '14 and shape an" elliptical entry.

in the seam of mineral. V Therotary cutting heads 14 that are secured tothe shafts 11 are'similar inconstruction and each has a hub or central portion 16 which is secured to-the shaft 11 by means of asplinei connection or the like. The hub. portion 16 has a pair of arms 17 and 18 extending radially predetermined size .is cut in the face of mineral.

therefrom in the same radial plane, and a core burster 19 secured to the hub portion front face. Sleeve members 20 and 21 are positioned over the radial end portions of the respective arms 17 and 18 in a manner that the sleeves 20 and 21 are not rotatable around the V longitudinal axis of the respective arms 17 and 18.

However, the sleeve members 20 and 21 are slidably positioned on the arms 17 and 18 so that the radial di mension between the sleeve members 20 and 21 and the hub portion 16 can be changed to either increase or decrease the overall diametrical dimension of the rotary cutting head 14. r a

As shown in Figures 2 and 3, each of the sleeves 20 and 21 has an outer tool holder 22 and an inner tool holder 23 secured thereto. The outer tool holder 22 has a body portion 24 and an inwardly flanged securing por-' of bolts or the like. (hitting bits 28 extend from the cutting tools 27 and are angularly spaced in relation to the tool holder front face portion 26 in order to cut an annular kerf in the face of mineral upon rotation of the rotary cutting head 14. V The inner tool holder 23 has a body portion 30 and securing flanges 31. The body portion 30 has a front face portion 32 with a plurality of cutting tools 33 secured thereto. Similar to the outer tool holder 22, the inner tool holder front face portion 32 is a circular segment with the center of the shaft 11 as the center of the circle. A plurality of cutting bits 34 extend from the cutting tools 33 and are spaced angularly relative to each other so that upon rotation of the rotary cutting head 14, the cutter bits 34 will cut an annular kerf in the face of mineral. The inner tool holders 23 are secured to the respective sleeves 20 or 21 by means of the securing flanges 31 abutting the front face of the respectivesleeves 20 or 21 and being secured thereto by means of bolts or the like. It should be noted that the inner tool holder 23 is spaced a predetermined distance from the outer'tool holder 22 so that an annular core of The inner tool holder 23' has a cam or built-up portion 35 extending radially outward from the body portion 30 which is adapted to burst and dislodge the annular core of mineral betweenthe inner tool holder 23 and the outer tool holder 22. I

It should be noted that the outer tool holders 22 are radially equidistant from the axis of the rotatable drive shaftll and upon rotation of the drive shaft 11, cut the same annular kerf. Similarly, the inner cutting tool holders 23 are radially equidistant from the axis of the rotatable shaft 11 and again upon rotation, cut the same second annular kerf in the face of mineral.

The core burster 19, shown in Figures 4 and 5, has a body portion 36, a front edge portion 37 and a rear flanged securing portion 38. A passageway 39 extends longitudinally through the body portion 36 and communicates with an aperture 40 in the wall of the body portion 36. The core burster rear flanged securing portion 38 has a plurality of apertures extending therethrough and is adapted to abut the front face of the rotary cutting head hub portion 16 and is secured thereto by means of bolts or the like. The core burster 19 is so positioned on the rotary cutting head 14 that it is axially aligned with the rotary drive shaft 11. A plurality of cutting tools 41 are secured I to the core burster front edge portion 37 and cutting bits 42 are secured therein. An offset cam or eccentric portion 43 extends radially from the body portion 36 and has an inclined front portion 44 which blends into the body portion 36, thus forming a wedge shaped cam por- 1 passageway 39 and an outer diameter less than the diam-V eter of the circular path formed by rotation of the cam portion 43.

A plate member 45 is positioned Within the body portion passageway 39 at an inclined angle to the longitudinaljaxis thereof and rearwardly beyond the wall aperture 40. The inclination of the plate 45 is such that the plate forms a deflecting wall which deflectsand guides any material within the passageway 39 through the wall aperture 40.

' Operation My new and improved rotary cutting head 11 is constructed to function substantially as follows. The mining machine housing 10 advances toward a vertical face of mineral with the rotary cutting heads 14 rotating on the horizontal drive shafts 11. As the mining machine advances into the face'of mineral, the cutting bits 42 on the core burster front edge portion 37 cut an annular kerf into the mineral seam with an inner diameter less v than the diameter of the core burster passageway 39 and an outer diameter less than the diameter of the circular path formed upon rotation of the core burster cam portion 43. As the core burster 19 penetrates the mineral scam, the cutter bits 28 on the outer tool holders 22 and the cutter bits 42 on the inner tool holders 23 simultaneously out two annular kerfs in, the face of mineral, the outer annular kerf being of greater diameter than the inner annular kerf.

As the mining machine continues to advance into the mineral seam, the cam portions35 on the inner tool holder body portion 39 burst and dislodge the mineral Within the annular core between the tool holders 22 and 23 and the coreburster cam portion 43 exerts a radially outward force or pressure against the annular portion of coal between the core burster body portion 36 and the innertool holders 23. This pressure from the cam por-; tion 43 will break the mineral away from the uncut mineral seam and allow the same to be picked upby the paddles -15 and directed toward the central conveyor means 13. The cylinder or inner core of mineral formed by the core burster cutting bits 42 enters the core burster lodging the cylindrical core within the passageway 39 and;

also guiding the dislodged portions of the cylinder through the core burster side Wall aperture 40.

It should be noted from the foregoing description and method of operation that my new and improved rotary cutting head now eliminates the difficulties encountered in existing rotary cutting heads and increases the overall;

efficiency of the continuous mining machine.

One of the reasons for this increase in overall efficiency;

is my new and improved core burster. Due to the specific construction of my core burster a relatively small inner annular kerf is cut into the face of the mineral leaving a central cylinder of mineral that enters the core burster'body portion passageway. With my core burster the mineral? at the center of the circular entry cutrby the.

rotary cutting head is no longer ground to a fine size Thus thesize consist'of the dislodged mineral is increased because actual cutting or grinding of the mineral by the ore burs e is m ni n zejdi a y' e ng s cr ase I I It is evident that the central. dislodging'means in my improved rotary cutting head has a greater. cutting ability per revolution of; the rotary cutting headthan any pres ently known mining machine of this type. new and l di led ins of? the.

improved core burster also eliminates the drillingorboring action at thev center ofjthe circular entry cut bythe rotary cutting head and presents a 'newmethod. of dis; lodging the central portion ofimineral; The positioning of the central cutting means-at a distance from the axial center of the rotary cutting head increases the lineal or cutting velocity of the center cutting means, per revoln tion of the, rotary cutting head as compared a d'r i l f ing means positioned at the center'of the rotary cutting on the inner tool' holders 23' also exert a positive type of bursting action.

The rotary cutting head also provides a new and improved method of dislodging minerals. The rotary cutting head cuts an outer' ker'f, an intermediate kerf and an inner kerf into the face of; mineral. The inner tool holders 23 which cut the intermediate kerf have a bursting means 35 positioned thereon which exert a force radially outward to -dislodge the mineral. between, the intermediate kerf and the; outer kerf; The coreburster 19 which cuts the inner kenf has a, bursting means 43 posi' tioned thereon which exerts a force radially outward to dislodge the mineral between the inner kerf and the intermediate kerf. The centralcylinder of mineral enters the core burster body portion 39 and is dislodged by means of the plate 45 and is discharged from the body portion 39 through the aperture 40. Thus, by my new method of dislodging minerals three kerfs are cut in the face of mineral and the mineral-between theikerf's' is effectively dislodged therefrom.

Another form of core bursteris shown in Figures '6 and 7 and is generally designated by the numeral 110. The

core burster 1 10 has a body portion 111 with externally threaded front end portion 112 and a rear flanged secur= ing portion 113. The body portion 111' has a passageway 114 therethrough and an aperture 115' in the wall of the body portion 111 which communicates with the passageway 114. The body portion 111 has a built-up annular ring portion 116 on its outer surfaces. between the aperture 115 and the threaded front edge 112. The

radial dimension of. the annular ring-like portion in respect to the longitudinal axis of the body portion 111 is not. uniform so that a projected longitudinal axis of the built-up portion 116 would be at an angle to the longitudinal. axis of the body portion 111 thus forming an eccentric or cam portion on the outer radial surface of the body portion 111. This is clearly shown in Figure 6 wherein the longitudinal axis of the body portion 111 is indicated by the letter A and the longitudinal axis of the built-up annular ring portion 116 is indicated by the letter B. The built-up portion 116 has a step-like bearing portion 117 thereon and a bearing member 118 is positioned around the bearing surface 117. A second bearing member 119 is positioned around the outer surface of the body portion 111 adjacent the externally threaded front edge 112. A conically shaped sleeve member 120 is positioned around the body portion 111. The sleeve member 126 has a rear step-like inner bearing surface 121 and a front inner bearing surface 122 which abut the respective bearings 118 and 119 and are freely rotatable thereon. A sealing ring 123 is positioned adjacent the front bearing 119 to prevent foreign material sea-seas rom enter be w n. he b a ng.. u, aq s.-. Th sleeve mem .20 s p urality f. on i u na y e tend fins 124' on its outer surface. An internally threaded cap member 12 5 is threadably secured on the front threaded edge of. the core burster-1T1 and' secures the sleeve member 120' thereon. 'The'capj member 1 25has a plurality of cuttingtool's 126 secured to its front face 127; cutting 'bitsf 128extendf forwardly from the cutting tool 126 at various angles in respect to the longitudinal axis of the body portion 111 and are adapted to cut an annular kerf in the mineral having an inner diameter less than the diameter of the passageway 114 and an outer diameter less; than the diameter of" the circular path formed bythe outer surface of the built-up ring portion 116. A plate, member. 129 is positioned within the passageway 114 rearwardly of the wall aperture and at an angle to the longitudinal axisofthe; passageway 114. The plate member 129' is adapted to deflect any of" the material within thepassageway 11-4 through the aperture 115. The core burster 110 is secured to the front face of the rotary cutting head hut; portion 16} in a manner similar to the core burster described in- Figure 4 with the longitudinal axis of the body portion 111 being coaxial with the longitudinal axis-of the rotatable drive shaft 11.

The core burster described herein with respect to Figures 6 and 7 breaks and dislodges the mineral in the following manner. As" the cuttingbits 128 penetrate themineral scam, the inner mineral core enters-the body portion passageway 114. As'the 'core'burster body portion 111 penetrates the-kerf' cut by the cutting bits 128, thesleeve member contacts the outer wall of the annular kerf and the fins 12,4 are wedged into the mineral and stop rotation of the sleeve member 120-. It should be noted that due'to the" specific construction oft-he annular ring portion 116, the longitudinal axis of the sleeve 120 and the core burster body portion 111 are coaxialadjacent the sleeve member front edgev portion. This permits even penetration of the sleeve member 120 to a point substantially beyond the sleeve member front edge. Continued penetration of the core burster 1'10 wili continue to wedge the fins 124 into the annular kerf outer wall and open cracks in the mineral. Due to: the fins 124', the sleeve. member 129 no longer rotates with the core burster body portion; 111 and the irregular radial dimensionof the built-up annular ringllfi' permits the, sleeve member 120, to exert an, irreg lar. radial Pressure or bursting action against the kerf. side, wall. The ac.- tion of the sleeve member 120 and the body portion built-up annular ring 116 will impart an eccentric type. of movement to the core burster 110 and thus burst or dislodge the annular core of coal between the. core burster 1-10- and the inner tool, holders 23,. An added advantage of the sleeve. member: 120 is. the, distribution of theradial pressure over. alarge: area.

Although. the two embodiments of this invention have been described with a pair oftool holders 22 and 23- on each of the arms 17- and 18, it should be understood that it is within the scope of this invention to provide the arms 17 and 18 or the sleeves 2'0 and 21 with either a single cutting means or a plurality of cutting means. It is also within the scope of this invention to provide the, rotary cutting head with either one, or more arms extending from the hub portion 16 and it is to be understood that this invention is not to be limited to the specific structure herein presented.

According to the provisions of the patent statutes, 1 have explained the principle, preferred construction, and mode of operation of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

1. A rotary cutting head adapted to cut a substantially vertical face'of material comprising in combination a rotatable shaft having an end portion, an arm extending radially from said shaft, cutting means carried by said arm in spaced relation to said shaft and operable upon rotation of said shaft to cut an annular kerf in said ma.- terial around and spaced from said shaft, a core, burster including a cylindrical core burster body,portion with a forward cutting portion and a rear mounting portion, said mounting portion secured to said shaft end portion with said body portion extending coaxially therefrom, said core burster body portion having a longitudinal. cylindrical passageway therein, said body portion having a first cylindrical external bearing surface adjacent said body portion forward cutting portion, said first cylindri cal bearing surface axis being angularly offset from said cylindrical core burster body portion axis and intersecting said core bursterbody portion axis adjacent said forward cutting portion, said body portionhaving a second cylindrical external bearing surface rearwardly of said first cylindrical bearing surface, said second cylindrical bearing surface axis being coaxially aligned with said first cylindrical bearing surface axis, a frusto-conical sleeve member having a front end portion and a rear end portion, a first cylindrical internal bearing surface formed adjacent said sleeve member front end portion and a second cylindrical internal bearing surface formed adjacent said sleeve member rear end portion, said sleeve member positioned over the outer surface of said body portion in a manner that the axis of said frus to-conical sleeve member is coincident'with said first and second cylindrical bearing surface axes, said first and second cylindrical bearing surfaces and said sleeve member first and second internal bearing surfaces coacting to permit free rotation of said sleeve member relative tov said burster body portion about an axis vangularly offset from said cylindrical core burster body portion axis, cutting means extending fromsaid body portion forward cutting portion, said cutting means being operable upon rotation of said shaft to cut a second annular kerf in said material .having an inner diameter less than the diameter of said body portion passageway and an outer diameter less than the diameter of said frusto-conical sleeve rear end portion, said sleeve member being operable upon rotation of said shaft to burst and dislodge the portion of said material between the inner circumference of said first named annular kerf and the outer circumference of said second annular kerf, said body portion passageway being adapted to receive the portion of said material within the inner circumference of said second named kerf, and means to discharge said last named portion of material from said body-portion passageway rearwardly of said frusto-conical sleeve.

2, A rotary cutting head adapted to cut a substantially vertical face of material comprising in combination a rotatable shaft having an end portion, an arm extending radially from said shaft, cutting means carried by said arm in spaced relation to said shaft and operable upon rotation of said shaft to cut an annular kerf in said material around and spaced from said shaft, a core burster including a cylindrical core burster body portion with a forward externally threaded portion and a rear mounting portion, said mounting portion secured to said conical sleeve.

shaftend portionwith said body portion extending co-. axially therefrom, said core burster body portion having a longitudinal cylindrical passageway therein, 7 said body portion having a first cylindrical externalbearing surface adjacent said'forward cutting portion, said first cylindri cal bearing surface axis being angularly offset from said cylindrical coreburster body portion axis and intersecting said core burster body portion axis adjacent said for-' ward threaded portion, said body portion having a second cylindrical external bearing surface rearwardly of said first cylindrical bearing surface, said second cylin-- drical bearing surface axis being coaxially aligned with said first cylindrical bearing surface axis, a frusto-conical sleevemember having a front end portion and a rear end portion, a first cylindrical internal bearing surface formed adjacent said sleeve member front end portion and. a second cylindrical internal bearing surface formed adjacent said sleeve member rear end portion, said sleeve member positionedover the outer surface of said body portion in a manner that the axis of said frusto-conical sleeve member is coincident with said first and second cylindrical bearing surface axes, said first and second cy-v lindrical bearing surfaces and said sleeve member first and second internal bearing surfaces coacting to permit free rotation of said sleeve member relative to said burste1 body portion about an axis angularly offset from said cylindrical core bursterbody portion axis, an annular cap member having a threaded internal surface and a plurality of cutting means projecting longitudinally there from removably threaded onto said cylindrical core burster body forward externally threadedportion, said annular cap member having a rearwardly projecting cylindrical flange which overhangs said frusto-conical sleeve member forward end portion, said annular cap member operable to secure all of said plurality of cutting means on said core burster body portion as a unit, said cut-, ting means being operable upon rotation of said shaft to cut a second annular kerf in said material havingan inner diameter less than the diameter of said body por tion passageway and an outer diameter less than the diameter of said frusto-conical sleeve rear end portion, said sleeve member being operable upon rotation of said shaft to burst and dislodge the portion of said material between the inner circumference of said first named annular kerf and the outer circumference of said second annular kerf, said body portion passageway being adapted to receive the portion of said material within the inner circumference of said second named kerf, and means to discharge said last named portion of material fromsaid body portion passageway rearwardly of said frusto- References Cited in the file of this patent UNITED STATES PATENTS 1,603,621 McKinlay Oct. 19,

2,594,256 Compton Apr. 22, 1952 2,720,391 McCarthy et al. Oct. 11, 1955 2,783,038 Tracy Feb. 26, 1957 OTHER REFERENCES Coal Mine Modernization, 1954, The American Mining Congress, Washington, D.C. Received in the Patent Oifice Library December 30, 1954; page 112. 

